With videos of shivering people flooding social feeds around the world, it’s safe to call this the summer of the Ice Bucket Challenge. And what a summer it was: we saw epic stunts, epic fails, quirky twists and a whole lot of celebrities. We learned a lot about the strange connections between famous people (Bill Gates knows Ryan Seacrest?). The IBC craze even resulted in a couple of marriage proposals. And it’s all in the name of charity: on September 7, the ALS Foundation reported more than $110 million in Ice Bucket Challenge donations.

The meme hit another major milestone this week, too: Ice Bucket Challenge videos have been watched on YouTube more than a billion times. That, combined with the volume of uploads, makes it one of the biggest video memes in the history of the Internet. Yeah, it’s that big.

The trend is also international. People from more than 150 countries have now posted "Ice Bucket" videos on YouTube, and "Ice Bucket Challenge" is August's top rising YouTube search globally. While 90 percent of videos came from the U.S. in the early days of the trend, within two weeks, the majority of IBC videos were uploaded from outside the U.S.:

As a charitable phenomenon, the Ice Bucket Challenge unprecedented in the history of YouTube. As a collaborative, participatory meme, it has a lot in common with last year’s explosive Harlem Shake. But it’s actually even bigger than Harlem Shake at its onset. In the first month after these memes took off, IBC has about double the uploads and three times as many views compared to the Harlem Shake.

Want to relive all the icy magic? Here are the most-watched IBC videos, ranked by views: